Field of the Invention
The present disclosure generally relates to a technique of correcting an image blur which occurs during panning with an image capturing apparatus and, more particularly, to an image blur correction apparatus, a method for controlling the same, and a storage medium.
Description of the Related Art
Panning has been known as a photographing technique to express a sense of speed of a moving object. This photographing technique is for causing a moving object to be static while a background to be blurred by a photographer panning a camera in accordance with a motion of the object. In panning, a photographer needs to pan the camera in accordance with a motion of the object. If a panning speed is excessively high or excessively low, a difference may arise between a moving speed of the object and the panning speed, whereby an image blur often occurs in an image of the object.
Japanese Patent Laid-Open No. 4-163535 discloses a method for correcting a shake of an object by moving a part of an optical system of a lens being exposed or an image capturing unit based on a “relative angular velocity of an object with respect to the image capturing apparatus calculated before the exposure” and an “angular velocity of the image capturing apparatus being exposed obtained from an angular velocity sensor.” The relative angular velocity of the object with respect to the image capturing apparatus is calculated from a “moving amount of the object on an image plane detected from temporally continuous images” and output of the “angular velocity sensor.”
In the related art method disclosed in Japanese Patent Laid-Open No. 4-163535, the moving amount for correcting a shake of the image of the object (i.e., an object shake) is calculated by moving a part of the optical system being exposed or the image capturing unit using a moving amount of the object on the image plane and the angular velocity of the image capturing apparatus. This calculation is performed on the premise that values of the “moving amount of the object on an image plane detected from temporally continuous images” and the “angular velocity of the image capturing apparatus being exposed obtained from the angular velocity sensor” are correct. For example, in an algorithm for detecting the “moving amount of the object on an image plane detected from temporally continuous images,” there is a problem that the moving amount of the object cannot be calculated unless the moving amount on the image plane equal to or greater than a predetermined threshold is detected. An exemplary case where a moving amount on an image plane equal to or greater than a predetermined threshold is not detected may be a case where case a necessary moving amount on an image plane is not obtained because the object focused on an angle of view to be focused on an image pickup device is small. There is also a case where a necessary moving amount on an image plane is not obtained if the object focused on the image pickup device has a low contrast.
In these cases, the operation to correct a shake of the object by moving a part of the optical system or the image capturing unit is ceased in the related art method.